Relay comprising sealed-in contacts



1961 F. PFLEIDERER 3,009,998

RELAY COMPRISING SEALED-IN CONTACTS Filed Sept. 10, 1958 United States Patent Ofiice 3,009,998 Patented Nov. 21, 1961 3,009,998 RELAY COMPRISING SEALED-IN CONTACTS Friedrich Pfleiderer, Munich-Solln, Germany, assignor to Siemens and Halske Aktiengesellschaft Berlin and Munich, a corporation of Germany Filed Sept. 10, 1958, Ser. No. 760,254 Claims priority, application Germany Sept. 20, 1957 7 Claims. (Cl. 200-87) This invention is concerned with a relay comprising sealed-in contacts.

The contacts in relays of the above indicated kind are operatively actuated by impressing upon the contact springs a magnetic flux which produces a field of force across the air gap, causing attraction of the contact springs and therewith closure of the contact points controlled thereby. In case the contact closure is to be effected electrically, an excitcr winding surrounding the sealed casing is employed for producing the flux to be impressed upon the contact springs.

The known excitcr winding for the actuation of sealedin contacts is in many cases a drawback. The reasons may be found in difficulties having to do with the space required for the exciter winding and among others in the fact that the inductivity of the exciter winding may have undesired consequences.

The invention shows a way for avoiding these drawbacks. The relay having the sealed-in contacts comprises, according to the invention, a permanent magnet the flux of which is closed by way of the contact springs and a magnetizable electrically conductive member, the magnetic conductivity of which is aifected by flux displacement by means of a control current connected to and flowing through the member to produce a flux flowing through the contact springs which effects operative actuation thereof.

The principle utilized by the invention may be employed for the operation of make contacts as well as for the operation of break contacts. In case of make contacts, the magnetizable. member is provided in the form of a magnetic shunt whichweakens the flux through the contact springs in normal condition to suchan extent that contact engagement cannot be effected, while producing for the actuation of the contacts a magnetic impedance opposed to the field of the permanent magnet,

due to the control current connected to and flowing through the shunt, so that the flux flowing in this condition over thecontact springs causes contact-making'engagement thereof. In the case of break contacts, the magnetizable member will vbe disposedas a magnetic impedance in asingle magnetic circuit including the permanent magnet and the contact springs, a flux flowing in normal condition over such circuit which causes closure of the contact springs; however, when controlcurrent is connected to the magnetizable member, the flux flowing through the contact springs will be weakened to such an extent that contact-making engagement is prevented and the springs accordingly open.

The various objects and features of the invention will appear from the description which is rendered below with reference to the accompanying drawing, wherein FIGS. 1 to 3 show examples of sealed-in make contacts comprising a magnetizable member as a shunt to a permanent magnet; and

FIG. 4 illustrates a sealed-in break contact comprising a magnetizable conductor acting as a magnetic impedance.

In the embodiment according to FIG. 1, make contact springs F1 and F2 are sealed in a tubular casing S having a permanent magnet D disposed adjacent thereto. The flux of the permanent magnet D, as indicated by arrows, extends on the one hand over the contact springs 2 F1 and F2 and on the other hand over a magnetic shunt N which is separated from the permanent magnet D by means of electrically insulating spacing members A. In the normal or resting condition of the relay device, the magnetic shunt N absorbs so much of the flux delivered by the permanent magnet D that the fluxflowing over the contact springs F1 and F2 is insufficientfor the operative contact-making operation thereof. However, when the magnetic shunt N, which is electrically conductive, is traversed by current which is suitably connected thereto, the flux produced therein by such current flow will be superimposed on the flux produced by the permanent magnet D. The first noted flux extends interiorly of the shunt circularly about the current flow, that is, perpendicularly to the flux delivered by the permanent magnet which extends in the direction of the longitudinal axis of the shunt or parallel to the current flow. The super imposing of the fluxes eflfects a displacement of the flux delivered by the permanent magnet D which is for practical purposes equivalent to a strengthening of the magnetic impedance of the shunt N with respect to the field of the permanent magnet D. The flux over the contact springs F1 and F2 consequently increases. This increase may be driven so far by increase of the current flowing through the magnetic shunt N that the contact points between the contact springs F1 and F2 are closed. The current traversing the shunt N accordingly acts as control current.

In the embodiment according to FIG. 2, the magnetic shunt N is disposed between the sealed tubing S and the permanent magnet D. This structure and arrangement acts in principle in the same manner as the example shown in FIG. 1, but the flux delivered by the permanent magnet D must permeate the magnetic shunt N so as to reach the contact springs F1 and F2. Accordingly, lower control currents are required for the operative actuation of the structure. The permanent magnet D must however be stronger. I

In FIGS. 1 and 2, the magnetic shunt N is shown as a simple elongatedconductor which may, for example, consist of a narrow, metallic strip. In order to produce with such a magnetic shunt the required flux displacement, by

current connected to the shunt, relatively high current will be necessary but low voltages will suflicer The use of high current is in most instances undesirable and the general endeavor will therefore be to utilize low curren strength in favor of higher voltage.

In the embodiment according to FIG. 3, the magnetic shunt consists of electrically conductive wire turns W disposed in undulating manner, such turns in their total length representing a higher electrical resistance than the magnetic shunts shown in FIGS. 1 and 2, but having at the same time magnetically only the length of the permanent magnet D disposed underneath thereof. The structure accordingly corresponds in its operative response to the embodiment illustrated in FIG. 1.

It is clear, of course, that the wire turns may be disposed between the permanent magnet and the sealed tubing, thus arriving at a structure corresponding to the embodiment shown in FIG. 2.

The example illustrated in FIG. 4 shows a sealed-in contact in its normal or resting position with the contact points of the springs F1 and F2 in contact-making engagement. A flux produced by a permanent magnet D is impressed on the contact springs F1 and F2 which elfects contact-making engagement of the contact points of the springs. In order to control this flux, the permanent magnet D is on the one hand magnetically connected with the contact spring F2 and on the other hand over a magnetic resistance V with the other contact spring F1. The magnetic resistance V constitutes the electrically c0nductive magnetizable shunt conductor. If a control current is caused to flow over the magnetic resistance V, the flux flowing over the contact springs will be weakened, causing the springs to separate so as to open the contact points thereof to break the circuit controlled thereby.

The magnetic resistance V, as mentioned in connection with the previously described embodiments, may of course be in the form of a metallic strip adapted for the desired purpose or in the form of a wire disposed in a plurality of undulating turns.

Known and suitable circuit means 'may be used throughout for connecting the control current to the electrically conductive and magnetizable control member such as M, W and V shown in the drawing.

It will be appreciated from the foregoing explanations that the invention oflers the possibility of actuating sealedin contacts electrically by means of connecting a control current to a control member without requiring an exciter winding.

Changes may be made within the scope and spirit of the appended claims which define What is believed to be new and desired to have protected by Letters Patent.

I claim:

1. In a relay having contact springs disposed in a sealed casing, a device for controlling the operative actuation of said contact springs, said device comprising a magnetizable and electrically conductive member adapted for connection to a current source to cause control current to flow therethrough, and a permanent magnet for producing a flux normally extending over said member and over said contact springs, said permanent magnet and member being disposed to operatively bridge said contact springs whereby current flowing through said member causes flux displacement therein affecting the mag netic conductivity thereof to produce a flux flowing over said contact springs which effects operative actuation thereof.

2. In a relay having contact springs disposed in a sealed casing, a device for controlling the operative actuation of said contact springs, said device comprising a magnetizable and electrically conductive member adapted for connection to a current source to cause control current to flow therethrough, a permanent magnet for producing a flux normally extending over said member and over said contact springs, current flowing through said member causing flux displacement therein affecting the magnetic conductivity thereof to produce a flux flowing over said contact springs which effects operative actuation thereof, said magnetizable member comprising a magnetic resistance, and means for connecting said resistance in a single magnetic circuit including said permanent magnet and said contact springs, flux normally flowing in said magnetic circuit effecting contact-making engagement of said contact springs, current flowing through said magnetic resistance being operative to weaken said flux so as to effect opening of said contact springs.

3. In a relay having contact springs disposed in a sealed casing, a device for controlling the operative actuation of said contact springs, said device comprising a magnetizable and electrically conductive member in the form of a metallic strip adapted for connection to a current source to cause control current to flow therethrough, and a permanent magnet for producing a flux normally extending over said member and over said contact springs, current flowing through said member causing flux displacement therein affecting the magnetic conductivity thereof to produce a flux flowing over said contact springs which eflects operative actuation thereof.

4. In a relay having contact springs disposed in a sealed casing, a device for controlling the operative actuation of said contact springs, said device comprising a magnetizable and electrically conductive member in the form of an undulating wire adapted for connection to a current source to cause control current to flow therethrough, and a permanent magnet for producing a flux normally extending over said member and over said contact springs,

current flowing through said member causing flux displacement therein affecting the magnetic conductivity thereof to produce a flux flowing over said contact springs which effects operative actuation thereof.

5. In a relay having contact springs disposed in a sealed casing, a device for controlling the operative actuation of said contact springs, said device comprising a magnetizable and electrically conductive member adapted for connection to a current source to cause control current to flow therethrough, and a permanent magnet for producing a flux normally extending over said member and over said contact springs, current flowing through said member causing flux displacement therein aflecting the magnetic conductivity thereof to produce a flux flowing over said contact springs which effects operative actuation thereof, said magnetizable member forming a magnetic shunt which is normally eifective to weaken the flux flowing over said contact springs so as to prevent con! tact-making actuation thereof, current flowing through said shunt producing a magnetic impedance opposed to the field of said permanent magnet to cause flux to flow over said contact springs which effects contact-making actuation thereof.

6. A structure and cooperation of parts according to claim 5, wherein said permanent magnet is disposed be-. tween said contact springs and said shunt.

7. A structure and cooperation of parts according to claim 5, wherein said shunt is disposed between'said permanent magnet and said contact springs.

References Cited in the file of this patent UNITED STATES PATENTS 2,169,827 Whitted Aug. 15, 1939 2,264,022 Ellwood Nov. 25, 1941 2,289,830 Ellwood July 14, 1942 2,821,597 Germanton et a1. Jan. 28, 1958 2,836,673 Reynolds May 27, 1958 2,877,315 Oliver Mar. 10, 1959 2,902,558 Peek Sept. 1, 1959 

